I’m now able to irritate a lot of my friends because I use Strava. The record-keeping is useful, and the segments — while they do prompt one to speed up when one might not want to — provide a nice progress report on one’s ability over certain parts of rides. But there’s one thing I’ve noticed: My speeds according to Strava are different from the speeds registered by my bike computer.
Now, I know I have el cheapo computer. However, I’ve been pretty satisfied with it. I measured the circumference of the front wheel by hand, and found that I need to enter 19 more millimeters than the 2096 commonly used for 23mm tires. My tires are 25mm, so 2115 mm is less than the suggested measurement for that size. Anyhow, when I compare my readouts to known distances on some of my more frequent rides, they are accurate to a level I find acceptable.
So I was puzzled when I noticed a difference between the stats in Strava and the stats on el cheapo. After the first couple of rides with both, Strava settled in and registered total distances for rides within one-tenth of a mile of my old computer. Even this morning, when I did a longer ride, the two were only four-tenths apart, and that was because I neglected to start my old computer at the beginning of the ride. I lost the data for about four blocks of riding.
But on Friday’s ride, there was a real disconnect. The problem area is maximum speed. For one downhill leg I do, the old computer clocked 31.9 mph. Strava had me at 36.4! That’s too much of a difference. Wonder what causes it? I also know from experience that the old computer’s speed was more likely to be the accurate of the two. I’ve ridden this stretch once or twice a week for the last several years, and I know what to expect. I also know what 36 mph feels like on my bike, and I didn’t have that feeling this time.
Therefore, while Strava is fun and useful, I have learned to be skeptical of it sometimes. I’ll continue to enter my ride stats on my spreadsheet (Yes, I know) according to my computer, and use Strava to gauge improvement.